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3-Methylpentane is a branched alkane with the molecular formula C 6 H 14. It is a structural isomer of hexane composed of a methyl group bonded to the third carbon atom in a pentane chain. It is of similar structure to the isomeric 2-methylpentane , which has the methyl group located on the second carbon of the pentane chain.
For example, NH 3 is a Lewis base, because it can donate its lone pair of electrons. Trimethylborane [(CH 3) 3 B] is a Lewis acid as it is capable of accepting a lone pair. In a Lewis adduct, the Lewis acid and base share an electron pair furnished by the Lewis base, forming a dative bond. [1]
Each bond consists of a pair of electrons, so if t is the total number of electrons to be placed and n is the number of single bonds just drawn, t−2n electrons remain to be placed. These are temporarily drawn as dots, one per electron, to a maximum of eight per atom (two in the case of hydrogen), minus two for each bond.
This would result in the geometry of a regular tetrahedron with each bond angle equal to arccos(− 1 / 3 ) ≈ 109.5°. However, the three hydrogen atoms are repelled by the electron lone pair in a way that the geometry is distorted to a trigonal pyramid (regular 3-sided pyramid) with bond angles of 107°.
In chemistry, electron counting is a formalism for assigning a number of valence electrons to individual atoms in a molecule. It is used for classifying compounds and for explaining or predicting their electronic structure and bonding. [1]
Therefore, for two electrons to occupy the same orbital, and thereby have the same orbital quantum number, they must have different spin quantum numbers. This also limits the number of electrons in the same orbital to two. The pairing of spins is often energetically favorable, and electron pairs therefore play a large role in chemistry.
An analogous consideration applies to water (one O lone pair is in a pure p orbital, another is in an sp x hybrid orbital). The question of whether it is conceptually useful to derive equivalent orbitals from symmetry-adapted ones, from the standpoint of bonding theory and pedagogy, is still a controversial one, with recent (2014 and 2015 ...
The rule is based on the fact that the valence orbitals in the electron configuration of transition metals consist of five (n−1)d orbitals, one ns orbital, and three np orbitals, where n is the principal quantum number. These orbitals can collectively accommodate 18 electrons as either bonding or non